the GNU version of the Collaborative International Dictionary of English
adj. Equally eternal.
The Century Dictionary and Cyclopedia
Existing with another from eternity.
Word Usage
"Thou my God, because Thou, O Father, in Him Who is the Beginning of our wisdom, Which is Thy Wisdom, born of Thyself, equal unto Thee and coeternal, that is, in Thy Son, createdst heaven and earth."